After reading the actual rumor and full OP, I have a better opinion now.
It will have to be an overall story line where initial conflicts arise, become over bearing, and then full victory is achieved by someone.
1-3 it was the rise and victory of the Sith. 4-6 was the rise and victory of the rebellion and the last Jedi, both sides alsmost vanquished.
I would think 7-9 would be the rise and seemingly victory of a new Sith army as a subset of the rebuilt Jedi order, finally ending with a massive war where both sides are brought back down in size and Sith being once again thought of as vanquished with the main hero also dying on the Jedi side.
So, part 7 starts out as a vibrant Jedi order begins to see hints of a dark side and there is constant strife as the Galactic Republic has been corrupted and is under attacks of rebellion/mutiny. By the end it is apparent the Sith there, but, not fully disclosed.
part 8 begins with a scene similar to that new game trailer with hundreds of sith attacking some Jedi outpost an the war is handily won by the sith. This movie is pretty much all small battles with mostly Sith wins, until a decisive battle at the end where some major Jedi/other good republic figures are killed or such so it leaves in a real down/dark moment.
part 9 continues with large wars and seemingly barely keeping hope alive, until one specific Jedi is able to unlock the rumored massive powers of Luke/Anakin that allow him to almost single handidly destroy groups of enemies at a time. His (or her) conquest finalize on a seemingly victory at the end where they actualy die, but only after a final onslaught the the sith main base where it seems like all sith are finally destroyed and control is returned to the republic/democratic group. But, the movie hints at a primary evil survivor.
My point is, it needs to be primarily about war. Not a long introduction of single characters which plagued episode one. We need to be thrown into a given conflict with proper dialogue that can fill in the backstory as it proceeds, like episode 6. Then continue through battles and battles with awesome force/saber fighting along with various other normal war scenes common in SW.